1. Field of the Invention
This invention relates to a control apparatus for a power window in an automobile, which has a safety function of detecting an accident in which a hand or the like is caught by or trapped in the power window during closing it.
2. Statement of the Prior Art
In a power window system in an automobile having four doors, in a driver's seat door there is generally provided a driver's seat window switch and a master switch for opening and closing windows in the passenger and rear seat doors. Sub-switches which open and close each window in the doors are provided in respective doors. The driver's seat window switch has two functions; i.e., an automatic function for automatically opening and closing the window in the driver's seat door into completely open and closed positions at a touch, and a manual function for opening and closing said window to an extent determined by depression of the switch. The master switch and sub-switches are generally provided to have only the latter manual function.
For convenience of explanation, a prior control apparatus in a power window system will be explained by referring to the drawing.
FIG. 7 shows an example of a connecting diagram of the prior control apparatus in the power window system. A power window relay 2 provided in a fuse box is connected at one end of an a-contact 2a via a main fuse 1 to a battery. The other end of the a-contact 2a is connected via fuses 3, 4, and 5 in the fuse box to normal open terminals of up side switch parts 6u, 7u, and 8u and down side switch parts 6d, 7d, 8d in a master switch 6 for a rear left seat, a master switch 7 for a rear right seat and a master switch 8 for a passenger's seat.
Also, the other end of the a-contact 2a in the power window relay 2 is connected via a fuse 9 in the fuse box to a power source terminal of a control unit 10 for the driver's seat power window. An automatic up input terminal AU, a manual up input terminal MU, a manual down input terminal MD, and an automatic down input terminal AD in the control unit 10 are connected to an automatic up terminal 11a, a manual up terminal 11b, a manual down terminal 11c, and an automatic down terminal 11d in the driver's seat power window switch 11, respectively. A changing-over piece 11e in the driver's seat power window switch 11 is connected to the earth together with an earth terminal in the control unit 10.
Further, a main switch 12 provided on the driver's seat door is connected between normal close terminals of the switch parts 6u, 6d, 7u, 7d, 8u, and 8d of the master switches 6 to 8 and the earth. By turning the main switch 12 on, each of the master switches 6 to 8 and each of sub-switches described hereinafter are enabled to operate. By turning the main switch 12 off, each of the master switches 6 to 8 and the sub-switches are prevented from operating.
A common terminal of both switch parts 6u and 6d in the master switch 6 for the rear left seat is connected to normal close terminals of an up side switch part 13u and a down side switch part 13d in a sub-switch 13 for the rear left seat. Normal open terminals of the switch parts 13u and 13d are connected via the fuse 3 to the other end of the a-contact 2a in the relay 2. A serial circuit including a circuit breaker 14 and a power window motor 15 for the rear left seat is connected between common terminals of the switch parts 13u and 13d.
A common terminal of both switch parts 7u and 7d in the master switch 7 for the rear right seat is connected to normal close terminals of an up side switch part 16u and a down side switch part 16d in a sub-switch for the rear right seat. Normal open terminals of the switch parts 16u and 16d are connected via the fuse 4 to the other end of the a-contact 2a in the relay 2. A serial circuit including a circuit breaker 17 and a power window motor 18 for the rear right seat is connected between common terminals of the switch parts 16u and 16d.
In addition, a common terminal of the switch parts 8u and 8d in the master switch 8 for the passenger's seat 8 is connected to normal close terminals of an up side switch part 19u and a down side switch part 19d in a sub-switch 19 for the passenger's seat. Normal open terminals of the both switch parts 19u and 19d are connected via a fuse 5 to the other end of the a-contact 2a in the relay 2. A serial circuit including a circuit breaker 20 and a power window motor 21 for the passenger's seat is connected between common terminals of the switch parts 19u and 19d.
A serial circuit including a circuit breaker 22 and a power window motor 23 for the driver's seat is connected between an up output terminal OU and a down output terminal OD in the control unit 10. A detector which detects complete open and closed positions of the window in the driver's seat in accordance with an amount of rotation of the motor 23 is provided between the earth and an input terminal for a detecting signal in the control unit 10. When the detector applies a detecting signal indicating the complete open or closed position to the control unit 10, an automatic opening or closing operation ceases.
A key-off timer circuit 24 is also provided in the fuse box. A power source terminal in the timer circuit 24 is connected via a fuse to the battery. A relay coil 2b in the power window relay 2 is connected between the earth and an output terminal of the timer circuit 24. The timer circuit 24 is energized by turning on an ignition key switch and maintains energization for a given period of time set by the timer after turning off the ignition key switch. During that period, the relay coil 2b maintains energization so that each of the switches 6 to 8, 11, 13, 16, and 19 are enabled to operate.
When the power window switch 11 for the driver's seat is changed over to the automatic up terminal 11a or the automatic down terminal 11d, a current from the control unit 10 flows in a closing direction or an opening direction in the power window motor 23 for the driver's seat, thereby automatically closing or opening the window in the driver's seat door into a completely closed or open position.
On the other hand, when the power window switch 11 for the driver's seat is changed over to the manual up terminal 11b or the manual down terminal 11c, a current from the control unit 10 flows in the closing direction or the opening direction in the driver's seat motor 23, thereby manually closing or opening the window in the driver's seat only during operation of the switch 11.
When each of the master switches 6 to 8 is changed over to the up side or down side, the up side switch parts 6u, 7u, and 8u or the down side switch parts 6d, 7d, and 8d in the switches 6 to 8 are changed over to the normal open terminals and a current flows in the closing or opening direction in the motors 15, 18, and 21 only during operation of the switches 6 to 8, thereby manually closing or opening the window in the rear seat doors, or the passenger's seat door.
Further, when each of the sub-switches 13, 16, and 19 is changed over to the up or down side, the up side switch parts 13u, 16u, and 19u or the down side switch parts 13d, 16d, and 19d in the switches 13, 16, and 19 are changed over to the normal open terminals and a current flows in the closing or opening direction in the motors 15, 18, and 21 only during operation of the switches 13, 16, and 19, thereby manually closing or opening the window in the rear right or left seat door, or the passenger seat door.
In the above construction, for example, if the master switch 6 for the rear left seat and the sub-switch 13 for the rear left seat are reversely operated simultaneously, that is, if the master switch 6 for the rear left seat is changed over to the down side while the up side switch part 13a is changed over to the normal open terminal by changing over the sub-switch for the rear left seat to the up side, the down switch part 6d of the master switch 6 is changed over to the normal open terminal when a current flows in the closing direction in the power window motor 15 for the passenger's seat via the normal open terminal of the up side switch part 13a. Thus, the power window motor 15 for the passenger's seat is stopped while it is rotating in the closing direction. The same result is obtained in the case that the other master switches and sub-switches are reversely operated at the same time.
On the other hand, when a hand, or the like is accidentally caught by the window by changing over the sub-switches 13, 16, and 19 in the other seat than the driver's seat, the hand or the like is released by changing over the sub-switch to the down side. However, a small child obviously cannot carry out such a switching operation.
It will be possible to release a hand or the like by changing over one of the master switches 6 to 8 in the associated seat to the down side in the driver's seat. However, if the master switch and the sub-switch are reversely operated at the same time, as mentioned above, the power window motor cannot rotate in the opening direction but stops. Consequently, it is impossible to release a hand or the like caught by the window. In the case of stopping the operation of the master switch, the power window motor may rotate again in the closing direction to continue to trap a hand or the like. Accordingly, there is a danger that the operation of the master switch cannot be stopped.
In order to prevent such an accident, for example, Japanese Patent Public Disclosure No. 61-78984 (1986) discloses a safety device for a power window. This device can prevent a hand or the like from becoming trapped during automatic opening and closing but this device is not directed to a device which stops the power window motor during manual opening and closing when the master switch and the sub-switch are reversely operated at the same time at the same time.